I have a Tyan S1856 updated to the most recent bios (2.00.02), which says that it supports cpus with 0683h cpuids, and I have a SL3XX pentium 3 that is under that 0683h id. However, the Tyan site (https://web.archive.org/web/20120425173337/ht … ii_celeron.html) says that the board doesn't support anything but celerons up to 533mhz. It boots fine with the 466 it came with. I don't really have a way to verify that the P3 is working, but when I turn on the power the heatsink does get warm.

Things I have tried:
Remove all power, remove cpu, set CMOS jumpers to clear, remove CMOS battery for a few minutes, hold the power button for 10+ seconds.
All of the above, but also remove gpu and ram
All of the above, but not moving the CMOS jumper
All of the above, but not removing the battery or the jumper
All of the above, but pushing the power button 30+ times instead of holding it

The silk screen has jumper settings for cpu speeds up to 700mhz, so it doesn't make sense for the board to cap out at 533mhz, but I guess overclocking may have been a consideration. I have the the jumpers set for 100mhz fsb and 7x multiplier, just in case.

Not really sure what to do from here.